MICROSCOPY. 119 
and Gundlach are prominent examples of those makers who seem 
to have adopted this policy of under-correction for color. 
Microscopy 1x New Jersey.— Mr. E. Gundlach, the celebrated 
proprietor of the Optical Institute at Charlottenburg, Prussia, has 
removed his residence to this country. He is now living at Hack- 
ensack, New Jersey, where he proposes to devote his attention 
exclusively to the manufacture of first-class objectives. 
DETERMINATION OF Powers IN THE COMPOUND MICROSCOPE.— 
This subject was discussed at a meeting of the Queckett club, and 
a variety of appliances recommended for the purpose. e sim- 
plest plan, and one familiarly employed by many microscopists, 
was advised by Mr. S. J. McIntyre who ascertained the, apparent 
size of the field of view, and reduced it to thousandths of an - 
inch, and divided that number by the number of divisions of a 
stage micrometer (ruled to thousandths of an inch), included in 
the field of view. Thus if the apparent field of view with a cer- 
tain ocular is five inches (93?) and with a certain objective it 
includes twenty-five divisions of a stage micrometer ruled to 
thousandths, then the power of the microscope as thus arranged 
will be ®32°—200. With another objective it may include four 
oa and the power will be *99°=1250. This plan is suffi- 
ciently accurate for practical purposes, and is, on the whole, the 
easiest method in use. 
Sections or Insrcts.— Mr. Henry N. Moseley advises to harden 
the insects by immersion for about a week in absolute alcohol. 
They are then, or any time afterward, to be embedded in a mix- 
ture of sweet oil and wax of suitable hardness, which he prefers 
to paraffin, and sections are to be cut with a sharp, thin edged 
razor wetted with absolute alcohol. The sections are to be imme- 
diately floated off on to slides, stained with carmine, treated with 
absolute alcohol and then with oil of cloves, and mounted in Can- 
ada balsåm or dammar varnish in the usual manner. Extremely 
beautiful specimens are thus prepared, showing the general anat- 
omy of the insect. Instructive objects are obtained pies sections 
passing through the eyes, especially if carried at the same time 
through the cephalic ganglia. The eyes of the mollusca, feo 
etc., may be similarly prepared. 
Starnine Tissues. Dr. R. L. Maddox has been studying the 
